It is often times necessary and/or desirable that a vehicle be caused to follow a straight line path or a plurality of parallel, evenly spaced straight line paths. Such is the case, for example, where agricultural vehicles must repeatedly traverse a field in parallel straight line paths in connection with a farming operation, such as, again by way of example, applying chemicals to a field. As is well known, it is difficult to traverse a straight line path with a vehicle unless the path is relatively well marked. Such is commonly not the case, however, in many farm fields at the time of chemical application and as a result parallel paths are often not well maintained in repeatedly traversing the field and this results in uneven coverage of the field, and can even result in missed areas as well as areas that might be harmed by over application of certain chemicals when applied to the field. Heretofore, it has been common to overlap application of chemicals to assure against missed areas, but this can lead to damage and is expensive due to waste of chemicals and fuel as well as increasing the time required for a given job. Furthermore, because of the present difficulty being experienced in attempting to maintain straight even paths, such work cannot be performed well at night or during other conditions of limited visibility.
While some devices for establishing straight line paths as well as equal spacing between paths has heretofore been attempted, no such device now known or utilized has been completely successful in accomplishing this end. In addition, no method has heretofore been known or utilized to enable a straight line path to be traversed and more particularly to allow a plurality of parallel straight line paths equally or otherwise spaced to be traversed.